title: Comparative study on sample stacking by moving reaction boundary formed with weak acid and weak or strong base in capillary electrophoresis: II. Experiments.
abstract: To demonstrate the theoretic method on the stacking of zwitterion with moving reaction boundary (MRB) in the accompanying paper, the relevant experiments were performed. The experimental results quantitatively show that (1) MRB velocity, including the comparisons between MRB and zwitterionic velocities, possesses key importance to the design of MRB stacking; (2) a much long front alkaline plug without sample should be injected before the sample injection for a complete stacking of zwitterion if sample buffer is prepared with strong base, conversely no such plug is needed if using a weak base as the sample buffer with proper concentration and pH value; (3) the presence of salt in MRB system holds dramatic effect on the MRB stacking if sample solution is a strong base, but has no effect if a weak alkali is used as sample solution; (4) all of the experiments of this paper, including the previous work, quantitatively manifest the theory and predictions shown in the accompanying paper. In addition, the so-called derivative MRB-induced re-stacking and transient FASI-induced re-stacking were also observed during the experiments, and the relevant mechanisms were briefly demonstrated with the results. The theory and its calculation procedures developed in the accompanying paper can be well used for the predictions to the MRB stacking of zwitterion in CE.
authors.affiliation: Laboratory of Analytical Biochemistry & Bio-separation, Key Laboratory of MOE for Microbial Metabolism and School of Life Science & Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Rd, Shanghai, 200240, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Liuyin
authors.initials: L
authors.lastname: Fan
authors.forename: Jing
authors.initials: J
authors.lastname: Shao
authors.forename: Si
authors.initials: S
authors.lastname: Li
authors.forename: Shan
authors.initials: S
authors.lastname: Li
authors.forename: Chengxi
authors.initials: C
authors.lastname: Cao
mesh_terms: D000143:Acids / Q000737:chemistry*; D000468:Alkalies / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000379:methods*
chemical_list: D000143:Acids; D000468:Alkalies